Alternator or isolator.?

[danwes]

2002 Winnebago, ultimate advantage. 40e. 350 Cummings. Alternator stopped charging. Both sets of battery's. Shore power or generator will charge both sets of battery's. How do I determined which is at fault. Isolator or alternator? Thanks Dan.

[Cloud_Dancer]

I'll try to link it:


http://www.prestolite.com/pgs_support/trouble_shoot_1.php

[Cloud_Dancer]

My guess is that your alternator has a failed brush, which would prevent it from charging.
Mine had the same symptoms, and I went through the drill of trying to learn all the controls of the 3 charging systems. I received a lot of help from the people on this forum.
I finally removed the alternator and had it checked at a specialty shop. I was told that the alternator had failed, and it would cost $250 to fix.
I took it and started looking into the alternator (trying to learn about it). I found one broken brush, and a rotor commutator which had burned carbon tracks on it. I fixed it myself by hand-sanding the commutator and installing new brushes ($18).

If your alternator looks like the one at the following web address, you will be able to see that the brushes are under the voltage regulator:

http://www.prestolite.com/pgs_support/trouble_shoot_1.php

[Jagtech]

Check the alternator output voltage, should be 13.5-14.25 volts, engine running. If that's low, the alternator is bad. If OK, then check for a possible fusible link, connected to the alternator, that might have burned out. (looks like a piece of wire, but will be marked "fuseable link".

[danwes]

Jolooote: alternator will not charge the engine start battery or the house battery; thanks for the reply. Dan

[jolooote]

When U say'both sets of batteries" do u mean two house batteries or both House & chassis(Engine) battery? If engine battery is charging than the alternator is ok.

[Rickieblue]

If I was checking it, I would put a voltmeter on a chassis battery and record the voltage not running, then after it is running, and then I would hook jumper cables directly from the alternator to the battery..that will eliminate a bad ground situation, a bad charge wire, and a bad isolator ..if the voltage then comes up on that battery..you will know your alternator will indeed charge and there is another issue.

[Clay_L]

Winnebago used a BIRD/BCC system in the Ultimate Advantage. It will charge the house batteries and engine battery from the converter and the engine battery and house battery from the alternator. The only model it was ever used on as far as I know.

They usually use a continuous duty solenoid that is activated by the run terminal on the ignition switch to allow the alternator to charge the house batteries when the engine is running. With the standard/usual system the house converter does not charge the engine battery.

I would call Winnebago and ask them about it.

[CA_Traveler]

If you have a diode type of isolator then it could be the problem. Otherwise the chassis battery should charge so check the alternator, wiring and related items.

[ksg5000]

Most tire/battery outlets will test your alternator for free - should eliminate one possibility.

[Gjac]

To check your alternator start the eng and check voltage across chassis battery, it should be about 14 volts or higher then check house batteries should be 14 volts or higher. If you don't see 14 volts check voltage directly off of the alternator. Post back your findings and you will get more help with you solenoids/isolaters.

[enblethen]

I doubt whether you have an isolator. You may have a regulator.
Check the alternator large terminal for 12+ volts output.

[Kayteg1]

Maybe both?
When you have no charging from engine at all, it has to be alternator.
When chassis battery gets power via insulator , the insulator is defective.